Freiprogrammierbare Steuerung

According to the invention, it is possible to relieve the software designer of complex organisational tasks during the design of software when functional tasks are called, by which means control functions are implemented for example, no longer by way of a central task such as the scheduler of a real time operation system, but by means of respective user-editable tasks in which measured values provided by the functional tasks are processed. Since the sampling time, for example of a control algorithm, is no longer a constant for the resulting non-equidistant functional calls, the respective sampling time must transmitted to the respective algorithms of the functional task as a parameter. Sampling time is particularly easy to determine if the functional tasks determine a time value with each call and calculate the sampling time themselves from the difference between the current time value and the previous time value. A time value can also be determined particularly easily if a time index register is requested. This time register is incremented with every call by a time index task which is called cyclically by the central task.